Shooting? That was too good for Billy...

Film-maker Don Boyd has a weakness for tales of society's criminal underbelly. But even his encounters with the Krays didn't prepare him for the time he spent researching Liverpool's drug barons with the Guardian crime writer Nick Davies. Here he tells the story of his dangerous months on the Mersey

The landscape of Liverpool is as evocative as Martin Scorsese's New York or Wong Kar-wai's Hong Kong, and yet it has been rarely used by British film-makers. Like those cities, it is rich in iconography, atmosphere and tradition; even in its present transitional guise, parts of the old docks and its Victorian inner city inspire a film-maker's imagination. Equally, it has a very rich cultural heritage and, being a port, has always attracted a wide range of extraordinary characters. It is separated from the rest of the country, almost an adjunct at the end of the M62, proudly guarding the magnificent estuary that has been the conduit for its wealth. It is no coincidence that it has been the port of entry for billions of pounds worth of drug traffic over the past 25 years.

I have always had an almost perverse desire to mix with people who make their living from crime. I suspect most people are secretly and similarly fascinated. Over the centuries, the lives of bad men have provided source material for many of our stories, songs and, of course, movies. Shakespeare created some spectacular villains; King Lear is stacked with them, men and women. When I was looking for a story to fit into the Liverpool criminal landscape, Lear seemed perfect.

I was introduced to the criminal world by David Puttnam, the now ennobled former film producer. Puttnam had been involved in John Pearson's definitive book about the Kray twins, The Profession of Violence, which I had optioned in 1989, and invited me to dinner at a famous underworld haunt in Soho to meet a friend of Ronnie Kray. Over white tablecloths, Gilbert France, a huge bear of a man with a thick French accent, ceremoniously showed Puttnam a pathetic scrawl etched out on the headed paper of Broadmoor special hospital, which was Ronnie Kray's home at the time. Kray wanted him to get hold of Puttnam and ask him what was happening about "my film". Without so much as a pause, Puttnam passed the letter to me and told France I was Ronnie's man.

Pearson had tried to make a film about the notorious twins at the time of their second trial, and I got the impression it had not been a happy experience. He generously warned me about the pitfalls of the gangster genre, especially in trying to portray living gangsters, who can dislike you on sight, or who can change their attitude to you because you flashed the wrong smile at the wrong time.

Over the next six years, I negotiated the ebb and flow of London's underworld with a boxing promoter called Alex Stein, who had known the Krays throughout their career. Always heavily bejewelled and sporting a magnificent pair of outsize stainless steel shades, this exotic tour guide chaperoned me throughout several visits to Broadmoor and the Isle of Wight to see the boys and regularly treated me to unmissable events: champagne evenings with Diana Dors, nightclub sessions with Charlie Kray and Joey Pile, family outings in the royal box at the London Palladium and cockney boxing galas as the guest of the imprisoned murderers. Probably the weirdest experience was my last visit to see Ronnie Kray in Broadmoor: breathing Silk Cut into my face from twitchy nostrils that were two inches away from my eyes at the time, Ronnie told me that if he didn't like my film, he could have me killed for "less than a monkey". I laughed and told him, somewhat existentially, that I didn't see the point of going to the trouble. He also thought that was very funny and ordered the attendant screws to bring the gift he had arranged for my wife - a pair of frilly pink knickers wrapped in a brown paper bag.

Stein reminded Kray tactfully that I could hardly portray the great man as being whiter than white.

"Whiter than white?" Kray roared. Then, in a sinister whisper wrapped around his trademark growly cackle of a laugh, he repeated "not whiter than white!", dug his knee deep into my thighs and blew some more smoke into my face.

On my way back into London after that visit I told Stein that I had had enough of unannounced visits at my offices from Kray aficionados, enough of nocturnal visits from plainclothes officers from the Metropolitan Police, enough of his "freebies" to Wimbledon and Wembley (there is always a price somewhere along the line). He was disappointed, but he seemed to understand. I sold my biographical rights with the Kray family (I had a contract with all of them, including one signed by their mother, Violet) and signed away my share in the option of Pearson's book so that somebody else could make Ronnie's film.

One story Stein told me, possibly inaccurately (that's the trouble in this arena - it is difficult to separate truth from hyperbole and mythology), has always stayed in my mind. It related to the Krays' one visit to Liverpool. Oddly enough, a similar story crops up in Pearson's book, in the context of a visit to Glasgow. In Stein's version, he, Ronnie and Reggie travelled to Liverpool determined to promote the first UK fight of the then Olympic champion Cassius Clay, now known as Muhammad Ali. As the trio emerged from the train at Liverpool Lime Street and began their ceremonial march down the platform of this magnificent glass-covered Victorian station, they were confronted by a threatening phalanx of huge Liverpudlians, dressed to kill in their double-breasted suits and shiny winklepickers. At the sight of this aggressive welcoming party, these scourges of Soho's underworld, then at the height of their violent notoriety, spun on the heels of their highly fashioned brogues and were never seen in Merseyside again.

On hearing this story, I promised myself that I would one day return to Liverpool, Europe's premier drug-dealing port, to investigate its underworld - and make the film that I had hoped to make about the London underworld with the Krays.

I confess to a love of the opportunities for drama inherent in criminal society. I love the characters and the iconography of their world - the weddings, funerals, council houses, pubs and nightclubs. When I finally arrived in Liverpool with my co-screenwriter, the Guardian crime journalist Nick Davies, we agreed that this city could provide the characters and landscape for our version of Lear in a way that the world of the Krays would never have done.

We were soon to meet Gerard Starkey, aka Ged, a man who, like Alex Stein in London, would provide me with an exotic tour of his city. I owe a lot of the detail of My Kingdom's Liverpool to Ged's people: to his extended Catholic family; to his lawyer, Andrew Pearson, who filled in so much background; and to other great characters like "Big Fat Stan", currently serving 10 years for his role in a cocaine importation operation. It was Stan who, while driving me around Liverpool with my two producers, pointed to a police helicopter hovering over the city and sneered in his Scouse accent: "German!" In Liverpool, wartime analogies epitomise the ancient divide between its respectable monied establishment and the under-classes who make up a large part of this city's criminal economy.

The Starkeys are loyal supporters of Everton football team and on Saturday afternoons are often at Goodison Park for the match. I met David Beckham there, once, at a Man United game, but I also shared a drink in the hospitality bar with a cluster of "faces" whose exploits would make your blood run cold. They were my first encounter with the characters who helped us most in constructing the script. Until then, Davies and I had only been scratching the surface.

These people are powerful, egotistic, ruthless businessmen, and to portray them wrongly would be to start a "war" - the sort that is usually declared over turf. Turf wars are settled with a "straightener", a particularly Scouse gangster phenomenon that involves the warring parties appointing a "champion" to settle the score with a bare-knuckle fight. The result is fiercely respected and accepted. This is also a society that does not welcome strangers.

As I reeled out of the football stadium, I couldn't help noticing the 10-year-old boys peering from underneath the huge team bus, excitedly clocking the names of these pillars of their community. These men have made millions "bringing in parcels" - a euphemism for importing drugs. They have maimed, killed and tortured to achieve their status; they are rugged, well-built and have a fierce sense of community; they are very intelligent and much more educated than they would have you believe. And their parties are the stuff of legend.

I was invited to a party to celebrate a successful and lucrative business deal. This involved three or four girls, a secret "safe" flat in the Albert Dock, the Thatcher-created luxury hinterland that is home to Curtis Warren, now serving 13 years in a Dutch prison for his crimes against society. Drug dealers are the nouveau riche in modern Liverpool and this swanky apartment was a far cry from the East End dives so beloved of the London criminal fraternity. Minders abounded, as did very fast, expensive cars and beautiful call girls fresh from one of the many fashionable Liverpool bars that are fuelled by drug money. But the sex on offer was almost an irrelevance to these hard-nosed and jubilant celebrants. They were more interested in exchanging the latest underworld gossip and telling me about what happened to the men I have come to call Billy the Wiz and Merv the Swerve.

Shooting was too good for Billy. Gun crime was commonplace on Merseyside during the late 1990s and getting rid of bodies is an awkward, messy business: a pair of mutilated corpses had, somewhat embarrassingly, recently been washed up on Morecambe Bay. There was also considerable unease about the very tacky and very public exploits of a family called the Campbell clan, famous for murderous orgies, snuff movies and bodies found on rubbish dumps wrapped in barbed wire. So what other punishment would fit Billy's transgression? I was told that he had been found screaming outside his house, unable to lie down because his body had been mutilated with a fish knife in the area of his buttocks; blood was gushing from the bottom of his torso. His back had been cut up as if he had undergone an autopsy. He later died from his injuries.

Merv the Swerve was "ironed" by way of punishment for grassing. He was tied to a wide wooden plank and then, with no doubt the latest and most efficient of steam irons... well you can guess the rest.

Why were they telling me all this? I guessed that Billy's executioners and Merv's torturers were warning me. I was mistrusted and under scrutiny. These hard men had heard about my exploits with the Krays. They knew about Davies's reputation. Was I really a film director? They wanted to help us with our research, or at least show willing. Any friend of Ged's! But we had to prove our trustworthiness. Gain "respect". They use this word a lot - the result of watching US gangster movies back to back in the little hours.

Davies, as a journalist, made the gangsters particularly nervous. He had already caused a fracas at the wedding of Ged's sister. Our invitation to this event was a great honour: the Starkeys are a very special and proud Liverpool family. Everybody who was anybody within Ged's community attended the Catholic service. The wedding had followed on from a very sombre family funeral we had also attended, so this was an opportunity to have some fun. The reception was held in a pub, and Ged and Stan provided a lavish feast. Davies befriended the daughter of the man they had all buried only a few days before: he was a single man with one of the pretty blondes in the pub. He was about to leave after we had all had gallons to drink and one of the inner circle took offence at Davies's behaviour: within moments he was surrounded and seen off without the blonde. This story about him circulated and contributed to a serious problem - and to my genuine fear that I might suffer the same fate as Merv.

I had felt from the day we arrived for the research process that we had been shadowed. On one occasion - late at night, tumbling out of one of Liverpool's luxurious downtown bars - our guide was accosted by an Asian man who had been watching us all evening. "All right then?" "Made up! Good to see you mate!" They chatted and slapped each other's backs, and when the stranger had disappeared, our guide said: "I hate that cunt!" Friendship in Liverpool gangsterland clearly turns on a penny, and it seemed that my acquaintances in the Albert Dock did not regard us as good enough friends to stop us being tailed.

Still, Davies and I went off on another surreal research trip that had been laid on for us. We had been told that we would get into an inner-city luxury brothel in Liverpool's Chinatown, but the only sex on offer there that night had came from the desperate purrs of the street prostitutes parading their almost naked bodies in the shadow of Liverpool's Anglican Cathedral. We spent the freezing night hanging ignominiously about outside burnt-out buildings in the ironically named Hope Street. What had we been up to, making frustrated mobile phone pleas to non-existent pimps? Pearson, the lawyer, had warned me that Ged's life was being threatened: his days owning Liverpool's most prolific and successful security company were coming back to haunt him. Ged is one of the most popular and best-known characters in Liverpool. If he wasn't safe, what about me?

Six months into writing the script, all the links to the community we had been writing about disappeared. There were no more friendly phone-calls, no more free rides to the house of one of Europe's most successful gangsters, no more girls or late-night drinking sessions. I was persona non grata. I soon learned why: the guys I had met at Goodison Park had put out the word that I had no intention of making a film and that I was a customs and excise stoolpigeon. They had apparently checked out John Hurt's commitment to the film and found out, quite rightly, that my early intention to feature him as Lear had been foiled by his refusal to accept the role. "John was his best friend, he told us! He was conning us!" How could I persuade them that the casting of famous actors is always precarious? And customs? During my exploits with the Krays - two of the most paranoid men I have ever come across - I had never been branded a spy.

I knew that without a lifeline to Liverpool's underworld my film was dead in the water. So, in desperation, I decided to camp out. I rented an apartment in the Liverpool suburb of Crosby and put the word out very proudly and very publicly that Richard Harris had agreed to play the main character.

When this fact filtered through, my old contacts and friendships slowly began to be renewed. Just before we began shooting My Kingdom, Harris and the cast were able to check out the haunts frequented by the kind of characters they were playing. Towards the end of the shoot, Harris threw a memorable party in a certain downtown bar. I remain very good friends with the man who introduced me to this world, Ged Starkey.

· My Kingdom is showing at the Crosby Plaza, Liverpool, on Tuesday and is on general release next Friday.